Enhancing Oxygenic Photosynthesis by Cross-Linked Perylenebisimide "Quantasomes"

J Am Chem Soc. 2022 Aug 10;144(31):14021-14025. doi: 10.1021/jacs.2c05857. Epub 2022 Jul 26.

Abstract

As the natural-born photoelectrolyzer for oxygen delivery, photosystem II (PSII) is hardly replicated with man-made constructs. However, building on the "quantasome" hypothesis ( Science 1964, 144, 1009-1011), PSII mimicry can be pared down to essentials by shaping a photocatalytic ensemble (from the Greek term "soma" = body) where visible-light quanta trigger water oxidation. PSII-inspired quantasomes (QS) readily self-assemble into hierarchical photosynthetic nanostacks, made of bis-cationic perylenebisimides (PBI2+) as chromophores and deca-anionic tetraruthenate polyoxometalates (Ru4POM) as water oxidation catalysts ( Nat. Chem. 2019, 11, 146-153). A combined supramolecular and click-chemistry strategy is used herein to interlock the PBI-QS with tetraethylene glycol (TEG) cross-linkers, yielding QS-TEGlock with increased water solvation, controlled growth, and up to a 340% enhancement of the oxygenic photocurrent compared to the first generation QS, as probed on 3D-inverse opal indium tin oxide electrodes at 8.5 sun irradiance (λ > 450 nm, 1.28 V vs RHE applied bias, TOFmax = 0.096 ± 0.005 s-1, FEO2 > 95%). Action spectra, catalyst mass-activity, light-management, photoelectrochemical impedance spectroscopy (PEIS) together with Raman mapping of TEG-templated hydration shells point to a key role of the cross-linked PBI/Ru4POM nanoarrays, where the interplay of hydrophilic/hydrophobic domains is reminiscent of PSII-rich natural thylakoids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Imides
  • Light
  • Oxidation-Reduction
  • Oxygen* / chemistry
  • Perylene / analogs & derivatives
  • Photosynthesis*
  • Photosystem II Protein Complex / chemistry
  • Water / chemistry

Substances

  • Imides
  • Photosystem II Protein Complex
  • perylene bisimide
  • Water
  • Perylene
  • Oxygen